Electric circuit breaker



June 30, 1942. o. c. PRINCE ELECTRIC CIRCUIT BREAKER Filed April 26, 1940 CONNECT/0N5 Invemtor: David CFrince, 1

His Attorney.

Patente d June 30, 1942 ELECTRIC CIRCUIT BREAKER David C. Prince, Swarthmore, Pa., assignor to General Electric Company, a corporation of New York Application April 26, 1940, Serial No. 331,796

(Cl. 20ll148) 8 Claims.

My invention relates to circuit breakers and more particularly to fluid-operated circuit breakers of the air-blast type.

Circuit breakers used in switching stations are often mounted in metal cubicles and, in installations of this kind. two positions of the circuit breaker in the cubicle are usually provided. One of these is the operating position of the circuit breaker while the other is often called the test position, that is, the circuit breaker is isolated from the associated electrical circuit but can be tested and operated mechanically. In circuit breakers depending to some extent upon fluid or gas under pressure for their operation, an additional problem arises over that of other types of circuit breakers since it is necessary to complete fluid connections such as gas or air connections as well as electrical connections before the circuit breaker can be operated. It would be desirable, therefore, to provide an electric circuit breaker requiring fluid under pressure for operation thereof which is adaptable for use in metal-clad switchgear wherein the external gas or air connections and the electrical connections to the circuit breaker may be completed by the same operation and these connections are such as to provide for both test and operating positions of the circuit breaker.

Accordingly, it is an object of my invention to provide a new and improved fluid-blast circuit breaker which is efficient in operation, simple and compact, and economical both from the standpoint of first cost and maintenance.

It is another object of my invention to provide a circuit breaker requiring fluid under pressure for operation thereof in which the external fluid and electrical connections to the circuit breaker may be completed or interrupted by the same operation.

Further objects and advantages of my invention will become apparent as the following description proceeds and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

My invention will be better understood from the following description taken in connection with the accompanying drawing in which Fig. 1 thereof is a cross-sectional View of a fluid-operated gas-blast circuit breaker embodying my in-' vention, and Fig. 2 is a sectional View taken in line 2-2 of Fig. 1.

Referring now to the drawing, I have illustrated my invention specifically as applied to a gas or air-blast circuit breaker comprising a suitable support or casing l0 and an arc chute ll of insulating material so arranged to form a unitary structure. For example, casing l0 and arc chute ll might be made from a synthetic casting resin and cast as a monolith. An example of such a resin is phenol-formaldehyde resin of the type or kind produced and sold by the Catalin Corporation of America under the trade-mark Catalin and described, for instance, in United States Patents 1,854,600; 1,858,168; 1,892,848; 1,909,786; 1,909,787; 1, 909,- 788; and 1,909,789.

The electrical circuit associated with casing l0 comprises a pair of conductors l2 and I3 which are rigidly mounted to extend through the walls of the casing iii of the circuit breaker and which have the portion extending exteriorly of the casing constructed in the form of a plug contact M which is arranged to make contact with a stationary female contact l5 of a well-known type which, in turn, may be suitably connected to bus bars or other external circuits, not shown. The end of conductor l3 extending into casing H] is provided with a stationary contact IB provided with a conventonal wipe spring ll. Preferably contact is has associated therewith an arcing tip l8 constructed of a suitable arc-resistant metal. Cooperating with stationary contact I6 is movable rod contact l9 pivotally mounted at 25 to the end of conductor l2 which extends into casing It.

Relative movement between contacts l6 and I9 is obtained through a suitable fluid motor comprising air-operated vane or piston 2| revolving about the same pivot or hinged joint 20 as movable rod contact l9. Casing I0 is shaped at Hla on the radius about pivot 20 and, furthermore, the side walls thereof comprise substantially fiat plates so as to fit closely around vane or piston 2 I. If desired, suitable leather fillets, not shown, may be provided on vane 2| so that a substantially gas-tight fit is obtained between vane 2! and the walls of casing l0.

Operation of the circuit breaker is obtained by means of a source or air or other gas under pressure, not shown, which causes rotation of vane 2| about pivot 20. Casing I0 is provided with air connections or tubular extensions 22 and 23 integrally formed therewith from insulating material, which are arranged to be inserted into stationary external air lines 24 and 25 so as to be telescopically engaged therewith to form slip joints 26 and 21, respectively. These air lines are provided with suitable gasket or sealing means 28 to prevent leakage of gas between the circuit breaker casing and the external air connections. Tubular extensions 22 and 23 of casing H] are arranged to extend for a considerable distance from casing ID as shown so that electrical contacts l4 and I5 may be disengaged without breaking the gas or air connections to the circuit breaker, whereby the operation of the circuit breaker may be tested before being connected into its power circuit. External air connections 24 and 25 are connected to a suitable source of air or other gas under pressure, not shown, which is controlled by suitable valves, also not shown. Since there is no pressure around gaskets 28 except during the opening and closing operations of the circuit breaker, the slip joints 26 and 2! provided between tubular extensions 22 and 23 and external gas connections 24 and 25 do not present any leakage problem. In air-blast circuit breakers using the nozzle device disclosed and claimed in my copending application, Serial No. 404,459, filed July 29, 1941, and assigned to the same assignee as the present application, it may be possible to dispense with the gaskets, such as 28, as will be Well understood by those skilled in the art.

I have illustrated my circuit breaker as of the latched closed type wherein a suitable latch 29 pivotally mounted to rod contact I9 is adapted to engage with a. cooperating keeper member 30 supported from the wall of casing I9 adjacent the free end of rod contact I9. A suitable spring means 3| biases latch 29 towards its latching position. Relative movement between contacts l6 and I9 is obtained by virtue of a pin 32 mounted in a recess 33 on vane 2|. When air is admitted to tubular extension 22 of casing l0, pressure is built up in the space below vane or piston 2| causing it to rotate in a counterclockwise direction about pivot 20. This movement causes pin 32 to rotate latch 29 in a counterclockwise direction, thereby releasing it from keeper 39. Further movement of vane 2| will cause pin 32 to engage the hook-shaped end 34 of latch 29, whereupon rod contact I9 is also rotated in a counterclockwise direction about hinge or pivot 29 so as to interrupt the electrical circuit and draw an arc between rod contact E9 and stationary contact I5. This movement of vane or piston 2| uncovers the orifice or opening 35 in casing II] which leads into arc chute so that a blast of air or other gas may escape through this orifice forcing the are drawn into arc chute II and against the edges of a plurality of baifies 35, only one of which is shown in the drawing.

Very efiicient interruption of the arc is obtained by this arrangement since a cross blast of gas or air is provided perpendicularly to the are drawn between contacts I6 and I9 driving it into arc chute II and against baflies 34. The operation of such a cross gas-blast circuit breaker as compared with other gas-blast breakers is described in the copending Price et a1. application referred to above. It will be understood by those skilled in the art that air or gas under pressure entering casing l0 through tubular extension 22 not only produces relative movement between contacts l6 and I9 but further supplies the cross gas-blast for arc-extinguishing purposes.

Closing movement of the circuit breaker is obtained by supplying air or other gas under pressure to casing I!) through tubular extension 23 thereof, whereby pressure is built up on the opposite side of vane or piston 2| causing clockwise rotation thereof as well as allowing rod contact l9 to move to the circuit-closing position.

Spring means 3| will cause latch 29 to engage with keeper 30 to hold the circuit breaker in the closed position until the next interruption operation. It will be understood by those skilled in the art that a suitable control means will be provided for controlling the air supply to stationary external air lines 24 and 25. Such a control arrangement may be similar to that disclosed in copending application Serial No. 310,599, filed December 22, 1939, on behalf of Bryce W. Wyman, now Patent 2,255,496, and assigned to the same assignee as the present application.

It will be observed that, with the arrangement described above due to inertia of vane 2| and the force of spring 3|, a gas pressure is built up between vane 2| and supply pipe or tubular extension 22 before movement of vane 2| occurs, and this pressure is then available for arc-extinguishing purposes by providing a blast of gas through orifice 35 after movement of vane 2|. It is, therefore, not necessary that tubular extension 22 be large enough to supply the gas blast on a continuous basis since this reserve pressure may be utilized.

The operation of my circuit breaker will be obvious to those skilled in the art in view of the detailed description included above. It will be observed that, in view of the arrangement of the slip joints 26 and 21 between the stationary external air lines 24 and 25 and the tubular extensions 22 and 23, respectively, of casing II], both the electrical and gas or air connections may be completed by a single operation, that is, by simply moving the entire circuit breaker relative to the stationary electrical and air or gas connections. Furthermore, the air connections are arranged to be completed in advance of the electrical connections so as to provide a test position for the circuit breaker. By constructing casing Ill, the arc chute II, and tubular extensions 22 and 23 as a unitary structure from a suitable insulating material, a very compact and economical construction is obtained.

While I have shown a particular embodiment of 'my invention as applied to a fluid-operated circuit breaker of the gas-blast type, it will be apparent to those skilled in the art that my invention is not limited to the particular construction shown but that changes and modifications may be made without departing from the spirit and scope of my invention and I aim in the appended claims to cover all such changes and modifications.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In an electric circuit breaker of the airblast type including a casing, a pair of relatively movable contacts mounted within said casing, electrical connections associated with said contacts and extending from said casing so as to be united with an external electrical circuit, air connections extending from said casing and arranged to be coupled with an external air circuit, and means for uniting said air and electrical connections extending from said casing with said external air and electric circuits by a single operation, said air connections being so constructed and arranged so as to be coupled with said external air circuit prior to the union of said electrical connections with said external electrical circuit so as to provide a test position for said circuit breaker.

2. In a fluid-operated circuit breaker of the gas-blast type including a casing, a pair of relatively movable contacts mounted within said casing, a fluid-operated motor for producing a relative movement between said contacts, latching means for holding said contacts in the closed circuit position, and means including said fluidoperated motor for first releasing said latching means and then producing relative movement between said contacts.

3. In a fluid-operated circuit breaker of the gas-blast type including an insulating casing and an arc chute formed as a unitary structure, a pair of relatively movable contacts and a fluid motor mounted within said casing, latching means pivotally mounted to one of said contacts for maintaining said circuit breaker in the closed circuit position, and means for causing said fluidoperated motor to release said latch and thereafter produce relative movement between said contacts to interrupt the electric circuit associated with said circuit breaker.

l. In a fluid-operated circuit breaker of the gas-blast type including an insulating casing and an arc chute formed as a unitary structure, a pair of relatively movable contacts mounted within said casing and arranged to draw an are upon separation thereof, one of said contacts being pivotally mounted, a fluid motor comprising a pivoted vane mounted within said casing, a latch for maintaining said circuit breaker in the closed circuit position, means for causing rotation of said pivotally mounted vane to release said latch and thereafter produce relative movement between said contacts to draw an arc, said last-mentioned means being arranged to drive said are into said arc chute upon movement of said pivotally mounted vane.

5. In a fluid-operated circuit breaker of the gas-blast type including a casing provided with an opening therein, an arc chute adjacent said opening, a pair of relatively movable contacts mounted within said casing and arranged to draw an arc upon separation thereof, a fluid motor comprising a pivoted vane mounted within said casing and arranged to cover said opening during the closed circuit position of said circuit breaker, a latch for maintaining said circuit breaker in said closed circuit position, and means for causing rotation of said pivotally mounted vane to release said latch and thereafter produce relative movement between said contacts to draw an arc and simultaneously to uncover said opening so that said last-mentioned means may drive said are into said are chute for interrupting the circuit rapidly.

6. In an electric circuit breaker of the type depending to at least some extent upon fluid under pressure for proper operation thereof including a casing, a pair of relatively movable contacts mounted within said casing, electrical connections associated with said contacts and extending from said casing so as to be connected with an external electrical circuit, fluid connections comprising a conduit portion extending from said casing and adapted to be telescopically engaged with a cooperating portion of an external fluid circuit, and means for uniting said fluid and electrical connections extending from said casing with said external fluid and electric circuits by relative movement of said casing with respect to said external circuits.

7. In an electric circuit breaker of the type depending to at least some extent upon gas under pressure for proper operation thereof including an insulating casing and an arc chute formed as a unitary structure, a pair of relatively movable contacts mounted within said casing, electrical connections associated with said contacts extending from said casing and arranged to be connected with an external electrical circuit, gas connections comprising conduit portions extending from said casing and adapted to be telescopically engaged with cooperating portions of an external gas circuit, and means for connecting said external gas and electric circuits to the corresponding connections extending from said casing by relative movement of the insulating casing of said circuit breaker with respect to said external circuits.

8. In an electric circuit breaker of the type depending to at least some extent upon gas under pressure for proper operation thereof including a support, a pair of relatively movable contacts, electrical connections associated with said contacts and extending from said support so as to be connected with an external electrical circuit, gas connections comprising a conduit portion extending from said support adapted to be telescopically engaged with a cooperating portion of an external gas circuit, and means for uniting said gas and electrical connections extending from said support with said external gas and electric circuits by relative movement of said support with respect to said external circuits.

DAVID C. PRINCE. 

